1. Field of the Invention
This invention relates to an image display apparatus, and more particularly, is suitably applied to an image display apparatus for supplying desired video data to a large video device used on the roof of a building, in an event site, or the like.
2. Description of the Related Art
A large video device having a large display is installed on the roof of a building, in an event site, or the like for displaying video images mainly for purposes of advertisement. A variety of commercial video images are simultaneously viewed by a large number of people with the large video device to achieve immense effects of advertisement.
As illustrated in FIG. 1, for example, a large video display system 100 has a variety of components installed at sites remote from each other, where the components are connected by cables 101 such as communication cables made of twisted copper fine lines, coaxial cables and optical fiber cables. Video sources such as a video tape recorder (hereinafter referred to as the xe2x80x9cVTRxe2x80x9d) 102 and a digital video disk player (hereinafter referred to as the xe2x80x9cDVDxe2x80x9d) 103 are switched by a switcher 104 to display a reproduced image on a large video device 105.
The large video display system 100 needs to be generally controlled by a person being in charge of this system with a main control unit 106 and a monitor 107 connected to the main control unit 106 in order to perform operations such as the control in accordance with the status of a video image reproduced by the large video device 105 and respective components of the system, and a recovery operation in case the system 100 fails.
In the above-mentioned large video display system 100, when the large video device 105 is installed in a building being remote beyond a street from a building having the main control unit 106 and the switcher 104 installed, the cables 101 must be placed by aerial-placing the cables 101 or by burying the cables 101 underground because respective components are connected by wired channels.
For aerial-placing the cables 101, for example, existing architectural structures such as poles may be utilized in many cases. For this purpose, however, the permission of the owner has to be obtained to utilize such architectural structures, and a large amount of fee will be charged for the rent. In addition, appropriate architectural structures are not always found at locations optimal to the aerial-placing of the cables 101. For newly constructing aerial cable placing facilities, a variety of applications must be made to the authorities for permission to the construction of such facilities, and a long construction term will be required.
On the other hand, for burying the cables 101 underground, similar authorization must be obtained for the construction work, and the construction work may often be limited in terms of the time depending on sites. In addition, the construction work will largely affect the civic life because of obstacle to the-traffic, tremendous noise caused thereby, and so on. As appreciated, the placing of the cables 101, in either of aerial or buried forms, for constructing the large video display system 100 involves a large number of working steps, a great deal of labor, and a long time, thus implying a problem in the lack of smooth progress in installing the system.
Furthermore, since the large video display system 100 constitutes a single closed system, difficulties are encountered for connection of the system 100 with another system located at a different site. Thus, a display associated with a large video device in another system would suffer from problems in that the same video sources must be provided in the other system, and very troublesome operations are required therefor.
In view of the foregoing, an object of this invention is to provide an image display apparatus which is capable of readily connecting an image data supply means and an image display means, which are located remotely from each other, by channels, and of offering a high usability.
The foregoing object and other objects of the invention have been achieved by the provision of an image display apparatus which comprises an image data supply means for supplying image data, an optic-spatial transmission means on a transmission side for emitting optical beam modulated in accordance with the image data, an optic-spatial transmission means on a reception side for receiving the optical beam emitted by the optic-spatial transmission means on the transmission side, and for demodulating the optical beam to recover the image data, and an image display means for displaying an image based on the image data recovered by the optic-spatial transmission means on the reception side.
Image data supplied from the image data supply means is converted into an optical beam which is then emitted, and the optical beam, when received, is demodulated to recover the image data which is then displayed on the image display means, so that even if the image data supply means and the image display means are installed at positions remote from each other, the image data can be optic-spatially transmitted. Therefore, a channel connection can be readily achieved without laborious and time-consuming works such as aerial-placing or underground installation of wired channels.
The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings in which like parts are designated by like reference numerals or characters.